Revenue bonds issued under this subpart shall bear the manual signatures or facsimile of the signatures of the chairperson and secretary of the board, and shall be sealed with the seal of the board or in lieu thereof shall bear a facsimile of seal. If the board designates a registrar other than itself for the revenue bonds, the resolution authorizing the revenue bonds may provide that none of the revenue bonds shall be valid or obligatory for any purpose unless authenticated by the registrar. If the resolution provides, all signatures of the board upon the revenue bonds may be facsimiles of the signatures, and the revenue bonds shall be valid and obligatory only if authenticated by the manual signature of an authorized officer or signatory of the registrar. Revenue bonds bearing the signature of officers in office at the date of the signing thereof shall be valid obligations, notwithstanding that before the delivery thereof and payment therefor any or all of the persons whose signatures appear thereon shall have ceased to be officers. The validity of the bonds shall not depend on or be affected by the validity or regularity of any proceedings relating to the construction or maintenance of the university project, university system, or network for which the revenue bonds were issued. The resolution authorizing the issuance of revenue bonds may provide that the bonds shall contain a recital that they are issued pursuant to this subpart, which recital shall be conclusive evidence of their validity and of the regularity of their issuance.